Regarding Packing Pressure

[krkkomal]

Can any body help me in understanding how to set Packing profile . Though i am able to understand the following steps

1) Gate Frreze time first from frozen layer fraction result
2) switch over time from the log file
3) Observe the decay time ,
4) Constant Pressure time
5) Decay time

But basic difficulty is in understanding how to get volumetric shrikage uniform after i set the initial profile to

Packing Time % Filling Pressure
0 80%

10 80%

Please anybody extend ur help in understanding this constant and decayed packing profile setting after viewing volumetric shrinkage at ejection to get uniform throughout the part with some example.

Thanks in Advance

Komal

[jean.uemura]

I have used the equations:

Constant Packing Time = t1 - (Injection Time)
Decay Time = t2 - t1
Cooling Time = t3 - (t1 + t2)

t1 = time to the end of filling reach No-Flow temperature
t2 = gate freeze time
t3 = time to all part reach ejection temperature

For e.g.:
CPT = 10s
DT = 5s
CT = 20s

Packing time x % Filling Pressure
0 80%
10 80%
5 0%
20 0%

That the initial and basic setup, then you can adjust the packing profile to optimize the vol shrinkage.


Jean Uemura

[madhukeshwart]

Steps are as follows

1. V/p switch over time (use text screen output i.e log) - T1
2. Gate freezing time (use frozen layer fraction plot )- T2
3. Take a plot of pressure at node (at end of fill node) -note down time at peak pressure and when pressure becomes zero( T3 & T4)
4. Then take average of T3 & T4 = T5
5. Constant pressure time T6= T5-T1
6. Decay time - T7 = T2-T5

Set packing profile - 0 80%,T6 80%,T7 0%. RUN ANALYSIS.

THEN ADJUST PROFILES AS REQUIRED ON BASIS OF REQUIRED LEVEL OF UNIFORMITY IN
VOLUMETRIC SHRIANKGE PLOT

[krkkomal]

Thanks Madhukeswar for your valuable information

Though i am able to get how to set initial packing pressure . Please let me know what r the steps followed to get uniform volumetric shrinkage.

At gate area: If volumetric shrinkage is high? If volumetric shrinkage is low?

At mid region:If volumetric shrinkage is high? If volumetric shrinkage is low?

At End region:If volumetric shrinkage is high? If volumetric shrinkage is low?

Please guide me with example


Regards

Komal KR

[krkkomal]

Thanks Madhukeswar for your valuable information

Though i am able to get how to set initial packing pressure . Please let me know what r the steps followed to get uniform volumetric shrinkage.

At gate area: If volumetric shrinkage is high? If volumetric shrinkage is low?

At mid region:If volumetric shrinkage is high? If volumetric shrinkage is low?

At End region:If volumetric shrinkage is high? If volumetric shrinkage is low?

Please guide me with example


Regards

Komal KR

[madhukeshwart]

At gate area: If volumetric shrinkage is high? If volumetric shrinkage is low?

If volumetric shrinkage is high at gate, increase decay time (T7).
If volumetric shrinkage is low at gate, decrease decay time (T7).



At mid region:If volumetric shrinkage is high? If volumetric shrinkage is low?

If volumetric shrinkage is high at mid, make one more stepped profile after constant time and change time and rate of decay and do trails


At End region:If volumetric shrinkage is high? If volumetric shrinkage is low

If volumetric shrinkage is high at end of fill , increase packing pressure , i.e set packing pressure > 80% , 90%, 100%, 110%, 120%.
and also increase constant pressure time (T6).

If volumetric shrinkage is low at end of fill ,decrease packing pressure , i.e set packing pressure <80 %, 60%,40%
and also decrease constant pressure time (T6).

[krkkomal]

HI Madukeswar

Thanks for your valuable infor

Regards

KRK

[teopado89]

"Take a plot of pressure at node (at end of fill node) -note down time at peak pressure and when pressure becomes zero( T3 & T4)"

Excuse me, how can i find T3 and T4? i didn't understand this.
Thanks in advance.

[madhukeshwart]

T3, is when pressure is high

T4, is when pressure is zero

[teopado89]

Ok maybe i have understand now.

I don't have to see the result "pressure at the end of fill", but create a new plot of pressure xy plot, then select one node in the last filled area and read from the xy graph the time of the highest value (T3) and when pressure drops to zero (T4) on the selected node in the end of fill area.

Is it right?

[madhukeshwart]

yes

[teopado89]

Thanks again

[madhukeshwart]

yes 

[teopado89]

Thanks!

[psofiagida]

Hi Sir,

for step 2. (gate freeze) i have my XY frozen layer plot. Should i check the time when the frozen fraction stops changing/increasing for the first time ?

Because for my case, that is at 19.9 sec, and i think it's a bit too big. So my decay time (T7 = T2-T5) will then be around 15.5 sec, which is exaggerated.

thanks.